Effects of gypsum-slotting on infiltration rates and moisture storage in a swelling clay soil

1986 ◽  
Vol 2 (3) ◽  
pp. 114-118 ◽  
Author(s):  
N.S. Jayawardane ◽  
J. Blackwell
Keyword(s):  
Clay Soil ◽  
Swelling Clay ◽  
Infiltration Rates ◽  
Moisture Storage

Aggregate breakdown in clay soils under simulated rain and effects on infiltration

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 111 ◽  
Author(s):  
SF Glanville ◽  
GD Smith
Keyword(s):  
Clay Soil ◽  
Aggregate Size ◽  
Clay Soils ◽  
Simulated Rainfall ◽  
Particle Size Range ◽  
Swelling Clay ◽  
Infiltration Rates ◽  
Aggregate Breakdown ◽  
The Impact ◽  
Wet Sieving

Wet sieving was used to separate aggregate-size distributions of four clay soils after pre-treatments of simulated rainfall, tension wetting and immersion wetting. Infiltration rates of columns of the soils were also measured under simulated rainfall. During rainfall, samples for wet sieving and the infiltrating columns were either bare or covered with a cloth mesh designed to absorb raindrop impact without affecting rates of wetting. Two swelling clay soils, one non-swelling clay soil and one clay soil dominated by sesquioxides, were used. For the first three soils, rate of wetting was the major factor governing aggregate breakdown. Significant changes in Mean Weight Diameter (MWD) occurred during the first few minutes of rainfall whether the samples were covered or not. As the rain continued, further breakdown was detected only in the uncovered samples. MWD of the sesquioxide soil decreased slightly during immersion, but most aggregate breakdown resulted from the impact of raindrops. Infiltration into the soil columns was virtually unrestricted if the soils were covered. Slaking without drop impact did not interfere with water entry. On bare soils, positive correlations were found between cumulative rainfall and the per cent of soil particles <0.12 mm diameter. An inverse relationship was found between this particle size range and infiltration rates. It is suggested that 25% of the <0.12 mm fraction must be present before infiltration rates decline.

Studies on potassium. IV. Interspecific differences in the uptake of non-exchangeable potassium

Soil Research ◽  
1974 ◽  
Vol 12 (2) ◽  
pp. 147 ◽  
Author(s):  
IF Fergus ◽  
AE Martin
Keyword(s):  
Soil Solution ◽  
Clay Soil ◽  
Plant Roots ◽  
Exchangeable Potassium ◽  
Swelling Clay ◽  
Rhodes Grass ◽  
Interspecific Differences ◽  
Chloris Gayana ◽  
Macroptilium Atropurpureum ◽  
Plant Removal

Five soils were cropped with four plant species in pot experiments in the glasshouse, without addition of potassium, until growth virtually ceased, after which the depleted soils were replanted with either the same species, or a different one, to test the reproducibility of the 'exhaustion' conditions imposed. Uptake of potassium by the plants exceeded the changes in exchangeable potassium in four soils; the excess amounts taken up differed markedly between species and these differences were reproducible on replanting. Uptake by setaria (Setaria anceps) and siratro (Macroptilium atropurpureum) exceeded that by Rhodes grass (Chloris gayana) and lucerne (Medicago sativa), except for one swelling clay soil from which uptake by lucerne equalled that by siratro. Most of the differences between species were attributed to the uptake of initially non-exchangeable potassium, which was removed in significant amounts from three of the soils. For these three soils, uptake from non-exchangeable sources was detected only after about 80% of the exchangeable potassium had been removed. It is postulated that the efficiency of plant removal of non-exchangeable potassium from soil is directly related to the degree to which plant roots can lower the concentration of potassium in the soil solution.

A STUDY OF MOISTURE STORAGE AND NITRATE ACCUMULATION IN SOIL AS RELATED TO WHEAT YIELDS ON FOUR CROPPING SEQUENCES

1961 ◽  
Vol 41 (1) ◽  
pp. 5-15 ◽  
Author(s):  
W. Michalyna ◽  
R. A. Hedlin
Keyword(s):  
Clay Soil ◽  
Mineral Fertilizer ◽  
Nitrate Accumulation ◽  
Fertilizer Use ◽  
Seeding Time ◽  
University Of Manitoba ◽  
Moisture Storage ◽  
The University ◽  
Relationship Of ◽  
The Relationship

On a clay soil at Winnipeg, Manitoba, at the University of Manitoba, four cropping sequences, namely: 1) fallow wheat; 2) fallow, wheat, wheat; 3) fallow, wheat, wheat, wheat; 4) wheat continuous have been under study since 1919. During the years 1956, 1957 and 1958 a detailed study of the relationship of wheat yields on these sequences to moisture consumption, nitrate accumulation, moisture storage and fertilizer use was undertaken. In general, yields were higher on fallowed than on non-fallowed plots. The higher yields on fallowed plots were, in part, related to nitrate accumulation during the fallow year. The yield differential between fallowed and non-fallowed plots was reduced by mineral fertilizer and manure treatments. Where no fertilizer was used the greatest wheat production in bushels per acre per year was on the fallow-wheat-wheat sequence. When fertilized or manured, the greatest production occurred on the wheat continuous plots.Rapid accumulation of moisture took place between harvest and the following spring. As a result, during years 1956, 1957 and 1958, there was only an average of 0.7 inches more available moisture to a 4-foot depth on fallow plots at seeding time than on plots which had been cropped the previous year.

Disposition of Fertilizer Nitrate Applied to a Swelling Clay Soil in the Field

1976 ◽  
Vol 5 (1) ◽  
pp. 66-71 ◽  
Author(s):  
D. E. Kissel ◽  
S. J. Smith ◽  
D. W. Dillow
Keyword(s):  
Clay Soil ◽  
Swelling Clay
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